Expiration Date for Spreadsheet

Expiration Date for Spreadsheet

Expiration Date for Spreadsheet

I have some spreadsheets I have created and want to protect. I have several people who want to use them under a licensing agreement. I would like to add an expiration date to the spreadsheets so that after a certain date, the spreadsheet no longer functions. Is there an easy way to accomplish (I know "easy" is relative, I am a novice+ Excel user)?

RE: Expiration Date for Spreadsheet

Besides which, the macro will have the desired effect for 99% of all users. That last 1% could probably figure out how to defeat the macro anyway. At some point, you reach the point of diminishing returns.

RE: Expiration Date for Spreadsheet

I would put conditional formating that will make the cells all black if the NOW() function is pass certain date. And maybe put a red statement saying it expires. Make sure you put a password so people cant edit it.

Never, but never question engineer's judgement

RE: Expiration Date for Spreadsheet

Presumably there's a way to re-save the sheet in disabled or otherwise unusable form so that it can't be re-opened with functionality restored by getting the PC to lie to the sheet about what the date really is . . . simultaneously with or immediately prior to the display of the expiration message might be an appropriate time to do that.

Norm

RE: Expiration Date for Spreadsheet

I have implemented expiry dates in some of my spreadsheets. My approach to NormPeterson's worry (that users - bless their little hearts - might crank their system clocks back) has been to have the spreadsheet keep track of the latest date on which it has been run.

This is stored, in encrypted form to make things a little harder for misbehavers, in the Registry. It allows me to detect reverse time travel, and treat it appropriately. (The VBA operations for this use GetSetting and SaveSetting.)